PLP trial outcome: nerve damage following third molar extraction

Originally published in March 2015

Mr. D was a 39-year-old accomplished bagpiper who was referred by his general dentist to oral and maxillofacial surgeon Dr. M for possible third molar extraction. The patient told Dr. M that his general dentist had seen “fluid” under the 48 two months before. Dr. M diagnosed pericoronitis of teeth 38 and 48, both of which were impacted and mildly tender without exudate. Dr. M recommended extraction of those teeth and the 28 as well, the 18 having been removed previously.

In light of the patient’s age, Dr. M warned him of the risk of sinus damage relating to the 28 and nerve injury arising from the lower extractions. Because he had personally observed a jaw fracture during wisdom tooth removal early in his career, he also advised the patient of that possibility. His notes of the consent discussion read:

Op; complications; sequelae explained, esp re poss sinus exp or nn injury or injury to adj. teeth or jaw #

The patient returned eight weeks later and signed a form consenting to the proposed treatment. Dr. M’s operative note states:

Extn of 28, 38, 48 c IV Sed – GA + LA via buccal flaps at all 3 sites c bur bone removal at all 3 sites & splits of 38 & 48 & indep retrieval of (ankylosed) roots from dense bone at all 3 sites

The extractions were complicated due to the depth of the impactions and orientation of the teeth, but tooth 48, which was completely fused to the jaw, proved especially challenging. During its removal, a jaw fracture with minimal displacement occurred and was immediately reduced with internal wire fixation and arch bars. Mr. D’s jaw was wired shut for approximately eight weeks. While the fracture healed without complication, he was left with permanent numbness of the lower right side of his jaw, chin and lip and could no longer play the bagpipes competitively.

Mr. D and his wife brought an action against Dr. M alleging absence of informed consent and negligent technique. He was supported by the opinion of a general dentist who concluded that the fracture itself was proof of excessive force and improper sectioning and, based on Mr. D’s evidence that the possibility of jaw fracture or numbness was not disclosed by Dr. M, that the patient’s consent was not informed. In his view, while the risk of mandibular fracture causing nerve damage would usually be too remote to be considered a material risk, the fact that this particular patient played a wind instrument created a heightened duty to warn.

An expert oral and maxillofacial surgeon retained for the defence opined that Dr. M’s work-up, diagnosis and treatment of the patient met the standard of care and his consent discussion actually exceeded what was required since jaw fracture during third molar surgery occurs too rarely to be disclosable. He also noted that the number of sections into which a tooth is cut and the force needed to perform an extraction are matters of judgment and that mandibular fractures and numbness can occur with wisdom tooth removal despite proper technique.

The matter proceeded to trial more than six years after Dr. M’s treatment and, in reasons for judgment released in September 2012, the trial judge dismissed the action with costs to the defendant.

The judge accepted that Dr. M’s contemporaneous notes accurately reflected the risks disclosed to Mr. D, including the possibility of numbness and fracture. He also accepted the testimony of Dr. M and his nurses that Dr. M’s invariable practice was to give such warnings to patients undergoing third molar extraction and to record those conversations. He found that the extractions were necessary and discounted Mr. D’s evidence that, had he known of the risks, he would have declined the surgery as being inconsistent with his history of following dental advice. Mr. D’s claim not to have read the consent form before signing it was further proof of his willingness to leave himself in Dr. M’s hands. In any event, the benefits of the treatment outweighed its risks, and a reasonable person, even one who played the bagpipes, would have consented.

As for the allegations of negligent technique, the judge preferred the opinion of the defence expert over the plaintiffs’ on all points. He found the plaintiffs’ expert report lacking in substance and criticized the expert for basing his assessment of the standard of care solely on his own experiences and rendering an opinion without properly reviewing the evidence. He noted that the defence expert had superior qualifications and grounded his opinion in statistical data rather than subjective impressions.

The plaintiffs’ appeal to the Court of Appeal of Ontario was dismissed with costs in March 2014 and leave to appeal to the Supreme Court of Canada was not sought. The action is therefore concluded.

Dr. M’s defence was greatly assisted by the quality of his consent discussion and record-keeping, and because he had invariable protocols to which others in his practice could attest. Without those things, the outcome of this case could have been different, despite the fact that Dr. M’s care was entirely appropriate.